How stress affects your brain - Madhumita Murgia

翻译人员: Jackson K 校对人员: Tianchang Luo

Are you sleeping restlessly,

你是否睡觉不安稳，

feeling irritable or moody,

感到易躁或者情绪化，

forgetting little things,

总是忘记一些小事情，

and feeling overwhelmed and isolated?

以及感到不堪重负和孤独？

Don't worry. We've all been there.

别担心，我们都经历过这些。

You're probably just stressed out.

你可能仅仅是压力太大。

Stress isn't always a bad thing.

压力并不总是件坏事，

It can be handy for a burst of extra energy and focus,

它会在某些时候帮助你 爆发额外的能量和专注力，

like when you're playing a competitive sport,

比如，在进行一项竞技性的运动

or have to speak in public.

或者必须在公众面前发言时。

But when its continuous,

但如果压力一直持续，

the kind most of us face day in and day out,

每天我们都接连不断地承受着压力，

it actually begins to change your brain.

它就开始实实在在地改变你的大脑。

Chronic stress,

慢性压力，

like being overworked or having arguments at home,

比如过度工作或家庭纷争，

can affect brain size,

会影响大脑尺寸、

its structure,

大脑结构

and how it functions,

和大脑功能，

right down to the level of your genes.

甚至会影响你的基因。

Stress begins with something called

压力开始于一种叫做

the hypothalamus pituitary adrenal axis,

下丘脑垂体肾上腺轴的东西，

a series of interactions

一连串的相互作用，

between endocrine glands in the brain and on the kidney,

在大脑的内分泌腺和肾脏之间，

which controls your body's reaction to stress.

它会控制身体对压力的反应。

When your brain detects a stressful situation,

当你的大脑检测到压力情况，

your HPA axis is instantly activated

你的下丘脑垂体肾上腺轴立刻会被激活，

and releases a hormone called cortisol, which primes your body for instant action.

并释放一种叫做皮质醇的激素， 提醒你的身体做好立即行动的准备。

But high levels of cortisol over long periods of time

但是高水平的皮质醇在一段长时间过后

wreak havoc on your brain.

会严重破坏你的大脑。

For example, chronic stress increases the activity level

例如，慢性压力会增加你大脑的活动水平

and number of neural connections in the amygdala,

和大脑恐惧中心——杏仁体

your brain's fear center.

的神经连接数量。

And as levels of cortisol rise,

随着皮质醇水平的上升，

electric signals in your hippocampus,

你海马体里面的电信号

the part of the brain associated with learning, memories, and stress control,

即大脑中和学习、记忆、压力控制相关的部分，

deteriorate.

开始恶化。

The hippocampus also inhibits the activity of the HPA axis,

海马体也抑制了下丘脑肾上腺轴的活动，

so when it weakens,

所以当它变弱，

so does your ability to control your stress.

你控制压力的能力也随之变弱了。

That's not all, though.

但是，这还不是全部。

Cortisol can literally cause your brain to shrink in size.

皮质醇实际上可以引起你大脑在尺寸上的萎缩，

Too much of it results in the loss of synaptic connections between neurons

过多的皮质醇导致神经原之间突触连接减少，

and the shrinking of your prefrontal cortex,

和你额叶前部皮质层的萎缩。

the part of your brain the regulates behaviors like concentration,

这是你大脑里管理精力集中、

decision-making,

决策制定、

judgement,

判断

and social interaction.

和社交互动的部分。

It also leads to fewer new brain cells being made in the hippocampus.

它也致使海马体中新生的脑细胞更少，

This means chronic stress might make it harder for you to learn

这意味着长期的压力可能使学习和记忆

and remember things,

对你而言更困难，

and also set the stage for more serious mental problems,

同时也留下了其他更严重的精神问题的隐患，

like depression and eventually Alzheimer's disease.

比如抑郁和最后的老年痴呆症。

The effects of stress may filter right down to your brain's DNA.

压力的影响可能直接渗透到你脑部的DNA。

An experiment showed

实验表明，

that the amount of nurturing a mother rat provides its newborn baby

一个雌鼠对她的孩子培育的情况，

plays a part in determining how that baby responds to stress later in life.

对于她的孩子在以后的生活中 会如何应对压力有一定影响。

The pups of nurturing moms turned out less sensitive to stress

被妈妈照顾得细致的鼠宝宝 会变得对压力比较不敏感，

because their brains developed more cortisol receptors,

因为他们的大脑里发展了更多的皮质醇受体，

which stick to cortisol and dampen the stress response.

和皮质醇紧密相关的皮质醇受体抑制了应激反应。

The pups of negligent moms had the opposite outcome,

被妈妈粗心大意喂养大的鼠宝宝就有相反的结果，

and so became more sensitive to stress throughout life.

所以 这些鼠宝宝在随后的一生里 都会对压力更加敏感。

These are considered epigenetic changes,

这些被认为是表观遗传变异，

meaning that they effect which genes are expressed

就是说它们在不直接更改基因代码的前提下，

without directly changing the genetic code.

影响了哪些基因被表现出来。

And these changes can be reversed if the moms are swapped.

如果雌鼠妈妈被交换，这些变化就会对调。

But there's a surprising result.

但是，还有个令人惊讶的实验结果。

The epigenetic changes caused by one single mother rat

一个鼠妈妈导致的表观遗传变异

were passed down to many generations of rats after her.

会被传递给她后面的好几代老鼠。

In other words, the results of these actions were inheritable.

换句话说，这些行为是会遗传的。

It's not all bad news, though.

但是，也不都是坏消息。

There are many ways to reverse what cortisol does to your stressed brain.

有许多不同的方式 可以改变皮质醇对你紧张的大脑的影响。

The most powerful weapons are exercise and meditation,

最有力的武器是锻炼和冥想，

which involves breathing deeply

因为做这些事情的时候你同时也会深呼吸，

and being aware and focused on your surroundings.

并关心和关注到你的周遭环境。

Both of these activities decrease your stress

这些活动减少了你的压力

and increase the size of the hippocampus,

增加了海马体的大小，

thereby improving your memory.

从而改善你的记忆。

So don't feel defeated by the pressures of daily life.

所以不要因为日常生活中的压力而感到挫败，

Get in control of your stress before it takes control of you.

人们只有控制好自己的压力 才不会反过来被它控制。